The invention relates to thinning scissors with one serrated cutting edge and one smooth cutting edge or with two serrated cutting edges.
When a cut is made with conventional thinning scissors provided, for example, with one serrated cutting edge and one smooth cutting edge, the hair grasped in strands by the thinning scissors is shortened by more or less the same length. This produces steps which are detrimental to the appearance of the hair-style. To prevent the steps, it is often preferable, for thinning, to use a razor, onto the blade of which is pushed a comb, the teeth of which project beyond the cutting edge of the razor blade. However, not only is a certain amount of dexterity required to handle a thinning instrument of this type, but it is also more time-consuming to thin by means of this instrument in comparison with thinning scissors. Moreover, the hair is split in a harmful way.
Thinning scissors with two serrated cutting edges are already known (German patent specification No. 932,476), and in these at least one scissor blade has a ground cutting edge at the bottom of each of the gashes. These thinning scissors are intended, in the first operation, to thin the hair roughly, that is to say not free of steps. In the second operation, the hair is then to be thinned out without steps, specifically solely by means of the scissor blade provided with the additional cutting edges. At the same time, the scissor blade is to be handled in a known manner in the same way as a razor with a comb pushed onto the blade. However, it becomes difficult to handle the scissor blade intended for thinning the hair without steps, because the other scissor blade has to be held in the position of rest during thinning. Thinning in two operations is also time-consuming.
In further known thinning scissors (German Auslegeschrift 1,228,160), for example the serrated cutting edge of a scissor blade is made corrugated, in order to cut off more hairs or fewer hairs from the strands grasped by the thinning scissors. If the scissors are rotated at an oblique angle relative to the direction of the hair strands, the uneven cutting of the hairs is intended also to be varied further, even to obtain differing hair lengths. Apart from the fact that the hair strands would not be thinned evenly, but in a highly variable manner, such thinning scissors are not even operable, specifically for the following reason. In any scissors, the scissor blades must touch one another with a certain pressure at the cutting edge, since a cutting effect is not obtained simply by sliding two cutting surfaces past one another. The pressing force at the point of contact between the cutting edges is generated as a result of the elastic resilience inherent in the scissor blades. When the thinning scissors are closed, the cutting edge of the non-serrated scissor blade, when it reaches a trough in the scissor blade having a corrugated serration, engages into the trough, with the result that, when the scissors are closed further, the non-serrated cutting edge comes up against the rising part of the trough and it is consequently impossible to close the scissors any further. The same applies to scissors in which the free ends of the teeth of the serrated scissor blade are arranged along a single elongate concave arc, since, when the scissors are closed, the cutting edge of the other scissor blade comes up against the front rising part of the arc, and again it is consequently impossible to close the scissors.